MATLAB程序看不懂

MATLAB程序看不懂[dx dy] = meshgrid(-r:r);h = exp(- (dx.^2 + dy.^2) / (2 * sigma_s^2));xp = padarray(x,[r r],’symmetric’);yp = padarray(y,[r r],’symmetric’);xt = zeros(size(x));parfor p = 1:numel(x),[i j] = ind2sub(size(x),p);求上面程序每步的注解!